Monetary tokens



Jan. 3, 1967 s. KLACKOWSKI ETAL 3,295,651

MONETARY TOKENS Filed March 25, 1963 FIG .1. 3

Ezee/ .5. fv/uar JE v/ws Lowe /?0/ 5744/7976 United States Patent3,295,651 MONETARY TOKENS Stefan Klackowski, Rnislip Manor, Barry BirchGoalby, Twyford, Dennis Charles Lowe, Whitley Bay, and Roy Salter, Newcastle-on-Tyne, England, assignors to Thomas de la Rue and CompanyLimited, London, England, a British company Filed Mar. 25, 1963, Ser.No. 267,548 Claims priority, application Great Britain, Mar. 26, 1962,11,441/ 62 8 Claims. (Cl. 1944) This invention relates to monetarytokens which can readily be distinguished from counterfeits, and to theproduction of such items.

Vending machines are commonly operated by the insertion therein ofcoins, the weight, shape and size of which are adapted, in any giveninstance, to cause the delivery mechanism to operate in accordancetherewith. With the development and increasing acceptance of vendingmachines, there is a need for tokens or other mechanism-actuatingdevices which represent greater monetary values than those of thelargest value coins now in use. Unmodified blanks of suitable weight,shape and size would not be suitable for this purpose because they couldbe virtually valueless per se and could easily be produced and usedfraudulently to cause machines to operate. Suitable tokens or otherdevices would necessarily have to include and to operate the deliverymechanism partly at least in accordance with a constant characteristicthereof, other than weight, shape or size, which has been speciallyimparted thereto and which cannot readily be created or reproduced byunauthorised persons.

It is an object of the present invention to provide such tokens.

According to the invention there is provided monetary tokens whichcomprise a radioactive isotope or element emitting a radiation of apredetermined penetration or energy level whereby the tokens can readilybe tested for authenticity.

A token according to the invention may comprise a radioactive materialwhich emits a radiation of a predetermined penetration range andintensity range. Such va token may be used to actuate the deliverymechanism of an automatic vending machine by the radiation emitted bythe token, the mechanism being actuated only by radiation of a givenpenetration range and intensity range.

Any convenient substance may be used as the base material for the tokenor other object, but preferably it includes one or more synthetic resinsin moulded, reinforced or laminated form. A preferred method of addingthe radioactivity is by using a radioactivity labelled compound whichreacts with the resin during the production of the token.

The radioactive isotope or element may be present in, on or beneath oneor both faces of the token, and may be mixed with the synthetic resin,contained in a reinforcing or carrier material for the resin, or presentin the form of ink or other marking or colouring ingredient appliedexternally or internally to the token. Additionally, the characteristicsof the tokens may be modified by including in the tokens a barriermaterial resistant to radiation and so capable of reducing the energy ofthe radiation actually emitted on either or both sides.

A suitable delivery mechanism actuable by the tokens of the presentinvention is actuated by an electric circuit which includes anelectronic component adapted to be influenced by a mechanism, forexample one or more Geiger-counter type devices, capable of beingactivated by the radiation emitted by the token.

Sensing mechanism systems involving differential activation of a pair ofsuitably interconnected Geiger-Muller Patented Jan. 3, 1967 tubes areparticularly advantageous. For example, when isotopes having lowpenetration energy of radiation are used, one Geiger-Muller tube may beadapted to he activated by radiation of low penetration energy and theother only by radiation of high penetration energy; the sensitivity ofthe latter tube may conveniently be restricted by providing its windowwit-h a shield, e.g. of thin aluminium. In such an instance the electriccircuit controlling the delivery mechanism is preferably arranged insuch a way that delivery occurs only when the Geiger-Muller tubeaccepting low penetration energy radiation is activated, but theGeiger-Muller tube accepting only high penetration energy radiation isreceiving only the degree of activity normally associated with abackground radiation from cosmic and other extraneous sources. A tokencontaining an isotope or element which emits particles with a highpenetration energy would cause both Geiger-Muller tubes to be activatedand delivery would not be effected.

In a two Geiger-Muller tube system the tubes may be placed to observe asingle active face or, alternatively, they may be placed one on eachside of the token. If the token has radioactive material on bothsurfaces a shield must be used to restrict the sensitivity of one of theGeiger-Muller tubes so that it will receive only high penetration energyradiation, but if a token having radioactive isotope on one side only isused the token itself can be used as a shield; the token can then beobserved by two identical tubes, one on either side, since by correctchoice of the materials used for the token it can be arranged that thetube remote from the radioactive side of the token is activated only ifthe isotope is of high penetration energy.

Alternatively, the electric circuit may be so arranged that the deliverymechanism is activated by tokens con taining isotopes of only highpenetration energy. In any arrangement it is preferable that theelectric circuits in the vending machine are so arranged that thedelivery mechanism is activated only when the energy or number ofparticles emitted by the radioactive isotopes lies between definedlimits.

The following methods for producing tokens according to this inventionare given by way of example only, do not limit the scope of theinvention, and will be described with reference to the accompanyingdrawings in which FIGURES 1 and 2 show broken away elevation- =al viewsof two difierent constructions of sheet material and FIGURE 3 shows aperspective view of a circular token.

Example 1 Referring to FIGURE 1, there are shown seven sheets 1 of 10mil kraft paper impregnated with 35-45% by weight of phenol-formaldehyderesin, cured to approximately the B stage, and assembled in a stack 2,and on one face of the stack 2 there is placed a 3 mil sheet 3 ofalpha-cellulose paper impregnated throughout with 60-65% by weight of amelamine-formaldehyde resin to which had been added a radioactiveisotope or element (carbon or uranium) in the form of a solublecompound. The carbon was added in the form of urea which can react withmelamine-formaldehyde resin.

The entire assembly was pressed between flat metal plates at 1500 p.s.i.and a temperature of C. to cure the resin and to consolidate the sheetsinto a unitary structure. The laminated product was then removed fromthe press and blanks 5 shown in FIGURE 3 having the diameter of a penny(about 1.25 inches) were cut from it.

Five tokens 5 were constructed as described, with differing amounts ofcarbon or uranium, as shown in the table, incorporated in the resin ofthe surface sheets on one side only.

The activity of these tokens measured on a conven tional thin windowGeiger-counter having an effective aperture of 0.9 inch diameter, was asfollows:

The tokens were inserted in a vending machine whose sensing mechanismcomprised an electric circuit including on one side of the token sensingposition a Geiger-Muller tube adapted to influence the circuitpositively when it received a number of emitted particles per minutewithin a predetermined range, and on the other side of Geiger- Mullertube adapted, in conjunction with the first tube, to influence thecircuit positively only when it received less than 30 emitted particlesper minute. Only Token 2 operated the delivery mechanism; Tokens 1, 3and 4 were unacceptable because their levels of activity were above orbelow the setting for the first tube and Token 5 was unacceptable foralthough the first tube received a number of particles within thepredetermined range and was thus activated, the second tube receivedmore than 30 emitted particles per minute because of the highpenetration energy of the isotope used, and so cancelled the positiveaction of the first.

Of course, the token must be inserted in the prescribed way, so that themelamine-formaldehyde resin layer faces the first tube, since otherwiseit will not operate the mechanism at all.

Example II Referring to FIGURE 2, there are shown seven sheets 1 ofkraft paper in a manner similar to those of Example I, with theexception that a three mil sheet 3 and 4 of alpha-cellulose paperimpregnated with 60-65 by weight of a melamine-formaldehyde resin towhich had been added a radioactvie isotope or element (carbon oruranium) in the form of a soluble compound was provided on both sides ofthe stack 2. From this laminated assembly there were produced fivefurther tokens similar to that shown at S-in FIGURE 3.

These tokens were inserted in a vending machine having the sensingmechanism described in Example I, with the exception that the secondGeiger-Muller tube adapted in conjunction with the first tube toinfluence the circuit positively only when it receives less than 30emitted particles per minute or equivalent energy was screened byaluminium foil .003 inch thick. The tokens operated the vendingmechanism in a manner identical to that described in Example I but itwas not necessary to insert the tokens any particular way round becausethe radioactive isotope was present on both faces and the aluminium foilreproduced the screening effect of the thickness of the single-sidedtokens in Example I.

From the above examples it is clear that the vending machine was able todistinguish both the energy and activity of the isotope or element used.The use of C is particularly advantageous since this isotope can only beobtained from a government controlled source and is only available toregistered users. The distinguishing of tokens made from this materialfrom those made using the comparatively readily obtainable salts oftitanium is thus of particular importance in ensuring that these tokenscannot easily be imitated.

The tokens according to this invention may, if desired, be provided witha removable protective covering or supplied in a protective container toeliminate any possible objections to their use on the grounds of healthhazard.

We claim:

1. A monetary token made from a material which includes radioactive ureacontaining carbon, and having a first surface having a substantiallyuniform distribution of carbon thereon, the emission of radioactivityfrom said surface being within predetermined ranges of penetration andintensity.

2. A monetary token as claimed in claim 1 having the radioactivematerial present in only one face of the token.

3. A monetary token as claimed in claim 1 having a second surface fromwhich there is no measurable emission of radioactivity.

4. A monetary token as claimed in claim 1 having a second surface on theopposite side from which there is an emission of radioactivity having auniform distribution over the whole of the surface, the radioactivityemitted from the second surface being within predetermined ranges ofpenetration and intensity different from ranges of radioactivity emittedfrom said first surface.

5. A monetary token as claimed in claim having a second surface on theopposite side from which there is an emission of radioactivity having auniform distribution over the whole surface, and the radioactivityemitted from the second surface being within predetermined ranges ofpenetration and intensity substantially the same as that emitted fromsaid first surface.

6. A monetary token comprising a disc of polymerised synthetic resinhaving a first surface containing a substantially uniform distributionof carbon entirely over said surface thereon to produce a uniformdistribution of emission of radioactivity within predetermined ranges ofintensity and penetration.

7. A monetary token comprising a disc of polymerised synthetic resinhaving a first surface containing a substantially uniform distributionof carbon thereon to produce a uniform distribution of emission ofradioactivity within predetermined ranges of intensity and penetration,said radioactive carbon being chemically combined in said polymerisedsynthetic resin, said resin comprising a radioactive urea compound and amelaminealdehyde condensation product.

8. A monetary token according to claim 7 wherein the melamine-aldehydecondensation product is a melamineformaldehyde resin.

References Cited by the Examiner UNITED STATES PATENTS 2,410,845 11/1946Snell et al. 1944 2,773,196 12/1956 Hall 250106 2,981,267 4/1961Stoddard 250106 X 2,983,354 5/1961 Ember et al. 1944 ROBERT B. REEVES,Primary Examiner.

ARCHIE R. BORCHELT, LOUIS J. DEMBO,

Examiners. S. H. TOLLBERG, Assistant Examiner.

1. A MONETARY TOKEN MADE FROM A MATERIAL WHICH INCLUDES RADIOACTIVE UREACONTAINING CARBON14, AND HAVING A FIRST SURFACE HAVING A SUBSTANTIALLYUNIFORM DISTRIBUTION OF CARBON14 THEREON, THE EMISSION OF RADIOACTIVITYFROM SAID SURFACE BEING WITHIN PREDETERMINED RANGES OF PENETRATION ANDINTENSITY.